squeezelite is not running

I 'm trying for days now to find a solution for a problem I ran into with piCorePlayer (4.0.0) and Raspberry pi (raspberry pi 3 model B V1.2) with a hifiberry dac+ .

It ran smoothly for a few days, but then it stopped working. Picoreplayer displays the message "Squeezelite is not running". I tried several fresh installs of pCP on the pi, installed it on another pi, tried older versions of pCP, bought a new microSD ... but nothing seems work.

My pi is connected with eth0 to my network. My LMS server is on the same network; it uses wifi. But all this was the same when it still worked.